ASTM C1215-18

Standard Guide for Preparing and Interpreting Precision and Bias Statements in Test Method Standards Used in the Nuclear Industry

SIGNIFICANCE AND USE
4.1 To describe the uncertainties of a standard test method, precision and bias statements are required.3 The formulation of these statements has been addressed from time to time, and at least two standards practices (Practices E177 and E691) have been issued. The 1986  Compilation of ASTM Standard Definitions  (6)4 devotes several pages to these terms. This guide should not be used in cases where small numbers of test results do not support statistical normality.  
4.2 The intent of this guide is to help analysts prepare and interpret precision and bias statements. It is essential that, when the terms are used, their meaning should be clear and easily understood.  
4.3 Appendix X1 provides the theoretical foundation for precision and bias concepts and Practice E691 addresses the problem of sources of variation. To illustrate the interplay between sources of variation and formulation of precision and bias statements, a hypothetical data set is analyzed in Appendix X2. This example shows that depending on how the data was collected, different precision and bias statements are possible. Reference to this example will be found throughout this guide.  
4.4 There has been much debate inside and outside the statistical community on the exact meaning of some statistical terms. Thus, following a number of the terms in Section 3 is a list of several ways in which that term has been used. This listing is not meant to indicate that these meanings are equivalent or equally acceptable. The purpose here is more to encourage clear definition of terms used than to take sides. For example, use of the term systematic error is discouraged by some. If it is to be used, the reader should be told exactly what is meant in the particular circumstance.  
4.5 This guide is intended as an aid to understanding the statistical concepts used in precision and bias statements. There is no intention that this be a self-contained introduction to statistics. Since many analysts have no formal sta...
SCOPE
1.1 This guide covers terminology useful for the preparation and interpretation of precision and bias statements. This guide does not recommend a specific error model or statistical method. It provides awareness of terminology and approaches and options to use for precision and bias statements.  
1.2 In formulating precision and bias statements, it is important to understand the statistical concepts involved and to identify the major sources of variation that affect results. Appendix X1 provides a brief summary of these concepts.  
1.3 To illustrate the statistical concepts and to demonstrate some sources of variation, a hypothetical data set has been analyzed in Appendix X2. Reference to this example is made throughout this guide.  
1.4 It is difficult and at times impossible to ship nuclear materials for interlaboratory testing. Thus, precision statements for test methods relating to nuclear materials will ordinarily reflect only within-laboratory variation.  
1.5 No units are used in this statistical analysis.  
1.6 This guide does not involve the use of materials, operations, or equipment and does not address any risk associated.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Jun-2018
• ICS: 27.120.01 - Nuclear energy in general
• Technical Committee: C26 - Nuclear Fuel Cycle
• Drafting Committee: C26.08 - Quality Assurance, Statistical Applications, and Reference Materials

Relations

• Refers: ASTM C859-14a - Standard Terminology Relating to Nuclear Materials
• Effective Date: 15-Jun-2014
• Referred By: ASTM C1009-21 - Standard Guide for Establishing and Maintaining a Quality Assurance Program for Analytical Laboratories Within the Nuclear Industry
• Effective Date: 01-Jul-2018
• Referred By: ASTM C1297-18 - Standard Guide for Qualification of Laboratory Analysts for the Analysis of Nuclear Fuel Cycle Materials
• Effective Date: 01-Jul-2018
• Referred By: ASTM D5792-10(2015) - Standard Practice for Generation of Environmental Data Related to Waste Management Activities: Development of Data Quality Objectives
• Effective Date: 01-Jul-2018
• Referred By: ASTM C1493-19 - Standard Test Method for Non-Destructive Assay of Nuclear Material in Waste by Passive and Active Neutron Counting Using a Differential Die-Away System
• Effective Date: 01-Jul-2018
• Referred By: ASTM C1429-21 - Standard Test Method for Isotopic Analysis of Uranium Hexafluoride by Double-Standard Multi-Collector Gas Mass Spectrometer
• Effective Date: 01-Jul-2018
• Referred By: ASTM C1156-18 - Standard Guide for Establishing Calibration for a Measurement Method Used to Analyze Nuclear Fuel Cycle Materials
• Effective Date: 01-Jul-2018
• Referred By: ASTM C1592/C1592M-21 - Standard Guide for Making Quality Nondestructive Assay Measurements
• Effective Date: 01-Jul-2018
• Referred By: ASTM C1133/C1133M-10(2018) - Standard Test Method for Nondestructive Assay of Special Nuclear Material in Low-Density Scrap and Waste by Segmented Passive Gamma-Ray Scanning
• Effective Date: 01-Jul-2018
• Referred By: ASTM E1893-15(2021) - Standard Guide for Selection and Use of Portable Radiological Survey Instruments for Performing In Situ Radiological Assessments to Support Unrestricted Release from Further Regulatory Controls
• Effective Date: 01-Jul-2018
• Referred By: ASTM C1316-08(2017) - Standard Test Method for Nondestructive Assay of Nuclear Material in Scrap and Waste by Passive-Active Neutron Counting Using ²⁵²Cf Shuffler
• Effective Date: 01-Jul-2018

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C1215 − 18
Standard Guide for
Preparing and Interpreting Precision and Bias Statements in
1
Test Method Standards Used in the Nuclear Industry
This standard is issued under the fixed designation C1215; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Test method standards are required to contain precision and bias statements. This guide contains a
glossary that explains various terms that often appear in these statements as well as an example
illustrating such statements for a specific set of data. Precision and bias statements are shown to vary
according to the conditions under which the data were collected.This guide emphasizes that the error
model (an algebraic expression that describes how the various sources of variation affect the
measurement) is an important consideration in the formation of precision and bias statements.
1. Scope Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.1 Thisguidecoversterminologyusefulforthepreparation
Barriers to Trade (TBT) Committee.
and interpretation of precision and bias statements. This guide
does not recommend a specific error model or statistical
2. Referenced Documents
method. It provides awareness of terminology and approaches
2
2.1 ASTM Standards:
and options to use for precision and bias statements.
C859Terminology Relating to Nuclear Materials
1.2 In formulating precision and bias statements, it is
E177Practice for Use of the Terms Precision and Bias in
importanttounderstandthestatisticalconceptsinvolvedandto
ASTM Test Methods
identify the major sources of variation that affect results.
E691Practice for Conducting an Interlaboratory Study to
Appendix X1 provides a brief summary of these concepts.
Determine the Precision of a Test Method
1.3 To illustrate the statistical concepts and to demonstrate
some sources of variation, a hypothetical data set has been 3. Terminology
analyzed in Appendix X2. Reference to this example is made
3.1 For definitions of terms used in this guide but not
throughout this guide.
defined herein, see Terminology C859.
1.4 It is difficult and at times impossible to ship nuclear
3.2 Terminology for Precision and Bias Statements
materialsforinterlaboratorytesting.Thus,precisionstatements
3.2.1 accuracy (see bias) —(1) bias. (2) the closeness of a
for test methods relating to nuclear materials will ordinarily
measured value to the true value. (3) the closeness of a
reflect only within-laboratory variation.
measured value to an accepted reference or standard value.
1.5 No units are used in this statistical analysis. 3.2.1.1 Discussion—For many investigators, accuracy is
attained only if a procedure is both precise and unbiased (see
1.6 This guide does not involve the use of materials,
bias). Because this blending of precision into accuracy can
operations, or equipment and does not address any risk
resultoccasionallyinincorrectanalysesandunclearstatements
associated.
of results, ASTM requires statement on bias instead of accu-
1.7 This international standard was developed in accor- 3
racy.
dance with internationally recognized principles on standard-
3.2.2 analysis of variance (ANOVA)—the body of statistical
ization established in the Decision on Principles for the
theory,methods,andpracticesinwhichthevariationinasetof
1
This guide is under the jurisdiction ofASTM Committee C26 on Nuclear Fuel
2
Cycle and is the direct responsibility of Subcommittee C26.08 on Quality For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Assurance, Statistical Applications, and Reference Materials. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
CurrenteditionapprovedJuly1,2018.PublishedJuly2018.Originallyapproved Standards volume information, refer to the standard’s Document Summary page on
ɛ1
in 1992. Last previous edition approved in 2012 as C1215–92 (2012) . DOI: the ASTM website.
3
10.1520/C1215-18. Refer to Form and Style for ASTM Standards, 8th Ed., 1989, ASTM.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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C1215 − 18
data is partitioned into identifiable sources of variation. mean. Note that the absence of sample size information
Sources of variation may include analysts, instruments, detracts from the usefulness of the confidence
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: C1215 − 92 (Reapproved 2012) C1215 − 18
Standard Guide for
Preparing and Interpreting Precision and Bias Statements in
1
Test Method Standards Used in the Nuclear Industry
This standard is issued under the fixed designation C1215; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1
ε NOTE—Changes were made editorially in June 2012.
INTRODUCTION
Test method standards are required to contain precision and bias statements. This guide contains a
glossary that explains various terms that often appear in these statements as well as an example
illustrating such statements for a specific set of data. Precision and bias statements are shown to vary
according to the conditions under which the data were collected. This guide emphasizes that the error
model (an algebraic expression that describes how the various sources of variation affect the
measurement) is an important consideration in the formation of precision and bias statements.
1. Scope
1.1 This guide covers terminology useful for the preparation and interpretation of precision and bias statements. This guide does
not recommend a specific error model or statistical method. It provides awareness of terminology and approaches and options to
use for precision and bias statements.
1.2 In formulating precision and bias statements, it is important to understand the statistical concepts involved and to identify
the major sources of variation that affect results. Appendix X1 provides a brief summary of these concepts.
1.3 To illustrate the statistical concepts and to demonstrate some sources of variation, a hypothetical data set has been analyzed
in Appendix X2. Reference to this example is made throughout this guide.
1.4 It is difficult and at times impossible to ship nuclear materials for interlaboratory testing. Thus, precision statements for test
methods relating to nuclear materials will ordinarily reflect only within-laboratory variation.
1.5 No units are used in this statistical analysis.
1.6 This guide does not involve the use of materials, operations, or equipment and does not address any risk associated.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
C859 Terminology Relating to Nuclear Materials
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
2.2 ANSI Standard:
3
ANSI N15.5 Statistical Terminology and Notation for Nuclear Materials Management
1
This guide is under the jurisdiction of ASTM Committee C26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.08 on Quality Assurance,
Statistical Applications, and Reference Materials.
Current edition approved June 1, 2012July 1, 2018. Published June 2012July 2018. Originally approved in 1992. Last previous edition approved in 20062012 as
ɛ1
C1215–92(2006).C1215 – 92 (2012) . DOI: 10.1520/C1215-92R12E01.10.1520/C1215-18.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
C1215 − 18
3. Terminology for Precision and Bias Statements
3.1 For definitions of terms used in this guide but not defined herein, see Terminology C859.
3.2 Definitions:Terminology for Precision and Bias Statements
3.2.1 accuracy (seebias) —(1) bias. (2) the closeness of a measured value to the true value. (3) the closeness of a measured value
to an accepted reference or standard value.
3.2.1.1 Discussion—
For many investigators, accuracy is attained only if a procedure is both precise and unbiased (see bias). Because this blending of
precision into accuracy can result occasionally in incorrect analyses and unclear statements of resu
...